There's also a worry that introducing chickenpox vaccination for all children could increase the risk of chickenpox and shingles in adults.

Chickenpox in adults

In adults, chickenpox tends to be more severe and the risk of complications increases with age.

If a childhood chickenpox vaccination programme was introduced, people would not catch chickenpox as children because the infection would no longer circulate in areas where the majority of children had been vaccinated.

This would leave unvaccinated children susceptible to contracting chickenpox as adults, when they are more likely to get a more serious infection, or in pregnancy, where there is a risk of the infection harming the baby.

Shingles in adults

We could also see a significant increase in cases of shingles in adults.

Being exposed to chickenpox as an adult – for example, through contact with infected children – boosts your immunity to shingles.

If you vaccinate children against chickenpox, you lose this natural boosting, so immunity in adults will drop and more shingles cases will occur.

So when is chickenpox vaccine given?

The chickenpox vaccine is used to immunise people who may pass the infection on to someone who is at risk of serious complications from chickenpox.

The vaccine may be given on the NHS to:

healthcare workers who are not immune to chickenpox

people in close contact with someone who has a weakened immune system

In this way, the chickenpox vaccine protects people at risk who are unable to themselves be vaccinated against chickenpox, such as: